The invention relates generally to video and audio signal encoding and decoding and manipulation, and in particular, to a method and apparatus for flexibly encoding and decoding multiple MPEG digital video and audio streams.
The television industry requires the availability of high quality, full motion audio and video signals, typically emanating from different sources. In U.S. Pat. No. 5,862,312, filed Oct. 24, 1995, issued Jan. 19, 1999, and entitled LOOSELY COUPLED-MASS STORAGE COMPUTER CLUSTER (the disclosure of which is incorporated herein, in its entirety, by reference), there is disclosed a system and method for reliably and continuously delivering multiple media streams even if one of the nodes of the described cluster were to fail. These streams are typically stored as MPEG encoded streams and/or compressed audio streams. It is important to be able to switch between the various streams in a seamless, continuous and reliable manner and to provide high quality audio and video signals having on-air broadcast quality.
As the technology develops, it is also important to be able to seamlessly switch between different MPEG streams, to provide multiple streams, and to decode incoming streams xe2x80x9con-the-flyxe2x80x9d so that no interruptions occur in the output video or audio.
The invention relates to a method for playing the decoded MPEG signals in a flexible and structured manner. In one aspect, the invention relates to receiving, at a high data rate, plural MPEG data encoded streams from at least one source, decoding the received streams, and synchronizing the multiple decoded streams to a reference clock.
In another aspect of the invention, there is provided a structure which allows the user to play multiple stream inputs simultaneously. The multiple output streams can have varying formats and can include both video and audio streams.
The invention also provides the ability to play any type of MPEG file immediately followed by another file and to do so seamlessly. The invention further provides the ability to skip B frames to obtain a desired reference frame quickly. Further, the invention enables the user to edit MPEG streams regardless of the GOP size. The editing can be accomplished for GOP sizes of two or greater.